The KSSN you registered with is either a child or teenager.
There was a new law in Korea, I believe, that prohibited children and teenagers to play from 12:00 am to 6:00 am.
That pops up whenever its 12:00 - 6:00 am, so you can't playing during those times.
KR:l 00 Qan[T] Full Saber l 00 Qan[T] l Zabanya (Final Battle Type) l Harute (Final Battle Type) l 00 Raiser l 00 7 Swords/G l
l 00 Raiser Condenser Type l Exia Repair II l l AGE-2 Normal l AGE-2 Double Bullet l Strike Noir (Twin Linear Guns) l